Sunday, June 29, 2014

Easy find

I found myself typing find . -name "*.java" | xargs -iHn "something"  so often I decided to make it into a bash script and put it in a new ~/Dropbox/bin folder so that I never have to do it again. Worse I never use the print0 option which let's you search files that have spaces in the filename, as it's too hard to remember. So, here's the script.

Monday, May 26, 2014

Sending notifications from Emacs (Mac OS X)

Sending notifications from emacs is something I find useful. In an earlier blog post I talked about how to use Growl to do so.

Well now you don't need Growl any longer. There's a neat github project called terminal notifier which let's you send notifications from the terminal.

You can install it simply, via Homebrew or Rubygems as follows:
$ [sudo] gem install terminal-notifier
brew install terminal-notifier
Then you can send notifications using a command like this:

terminal-notifier -message "hello"

Finally in order to send the notification from emacs we need to write a little Emacs lisp.

Check out this gist for the code I use:

This lets you send a notification in the future using M-x timed-notification

You are prompted for a time, and the format of that time can be given in a human readable way such as "2 seconds" or "5 minutes" (If you're curious for the allowed options look at the info page in emacs for the function timer-duration )

Then you are prompted for the message "Go to the store", and the message will be sent.

The code is very simple, it simply uses run-at-time to run the terminal command in the future. A useful command is find-executable, which given a name will find that executable in your path and run it. This makes configuring tools like this less effort.


Hey if it doesn't work first time what can you do?

  1. Check if terminal notify is installed correctly by running at terminal
  2. If that succeeds and you don't get a message check if you have enabled do not disturb mode
  3. Otherwise if that succeeds and yet emacs isn't sending messages you likely don't have the executable on the path. M-x customize-variable exec-path

Tuesday, April 1, 2014


So this is pretty cool.

The watch command (available linux and on Mac via brew) will run a program every n seconds and display the results in a terminal.

For example, the following common will show the display above with human readable disk free space on your system. But since the command can be anything you want this is a pretty powerful tool.

watch -n 3 df -h

Wednesday, March 12, 2014

Checkout out your DB tables

I was doing some DB work today and wanted to be able to sort all DB tables based on the date they were created. Turns out you can do some neat stuff by looking in the information_schema.tables. For example this shows all the InnoDB tables.

select `table_schema`, `table_name`, `create_time`  FROM information_schema.tables where engine = 'InnoDB' order by create_time desc  ;

Wednesday, February 6, 2013

Configuring emacs to send iCloud mail on Mac OS X

Pic from ajc1 on Flikr
It's handy to be able to send emails from emacs, and this guide will show how to set up SMTP via an iCloud email account.

Step 1. Install gnutls

iCloud requires you to send emails over secure channel, and emacs supports sending email with starttls or gnutls. gnutls is available through brew

To install it is easy:

brew install gnutls

Wait a few minutes while your Mac gets hot downloading and compiling!

Step 2. Create an authinfo file

emacs can look in a file ~/.authinfo to find your login credentials, so create that file and fill in the blanks.

touch ~/.authinfo
chmod 600 ~/.authinfo

The contents of the file should read:

machine port 587 login password YOURPASSWORD
Step 3. Configure emacs

Add the following to your .emacs file:

 send-mail-function 'smtpmail-send-it
 message-send-mail-function 'smtpmail-send-it
 user-mail-address ""
 user-full-name "YOUR FULLNAME"
 smtpmail-starttls-credentials '(("" 587 nil nil))
 smtpmail-auth-credentials  (expand-file-name "~/.authinfo")
 smtpmail-default-smtp-server ""
 smtpmail-smtp-server ""
 smtpmail-smtp-service 587
 smtpmail-debug-info t
 starttls-extra-arguments nil
 starttls-gnutls-program (executable-find "gnutls-cli")
 smtpmail-warn-about-unknown-extensions t
 starttls-use-gnutls t)

Note that your gnutls program may be in a different spot. Find it with:

mdfind -name gnutls-cli 
Step 4. Testing

To compose an email C-x m

Enter an email and hit C-c c to send it.

If it works, great! If not switch to the *Messages* buffer for hints on what may have gone wrong.

Step 5. Sending emails from elisp code

(message-mail recipient subject)

Sunday, April 29, 2012

find grep on Mac OS X

On linux machines I search files using find, egrep and xargs as follows:

  find . -name "*.cpp" | xargs -i egrep -iHn "some search string" {}

this outputs any matches with the filename and number and also disables case dependency.

On my Mac it doesn't work. I tried reverting to egrep -r (to search recursively) instead, but that doesn't work. It just fails silently too. I tried installing findutils with brew to see if that helped, as often gnu tools are more up to date in brew than in the Apple version, but that didn't help.

So after some fiddling I found that the syntax below works:

  find . -name "*.cpp" | xargs egrep -iHn "some search string"

Only subtly different!

Actually, hold up, this does not work for filenames that have spaces in them. :(

Try this instead:

find . -type f -print0 | xargs -0 egrep -iHn "some search string"


Thursday, March 22, 2012

Starting a program to run in the background from a DOS prompt

Picture by ro_buk on Flickr

From a bash shell you can run a command in the background by adding an "&" to the end of the command, but how do you do the same thing in Windows?

Using the START command lets you run a task in the background (maximised or minimised), or in the foreground.

For example the following would run memcached in the background minimized.

C:\>start /min D:\platform\memcached.exe

Microsoft's documentation is below, but it seems the options have changed. /m does not work but /min does.

Microsoft's documentation on START